Jews, Christians and submitters: is our god one and the same?

The Quran tells its readers how to open this conversation: "Do not argue with the people of the scripture (Jews, Christians, and Muslims) except in the nicest possible manner - unless they transgress - and say, 'We believe in what was revealed to us and in what was revealed to you, and our god and your god is one and the same; to Him we are submitters.'" (29:46) Jesus answered the first commandment with the Shema: "Hear, O Israel; The Lord our God is one Lord" (Mark 12:29, KJV). Where do you find common ground first, and where do you think we really differ?